Background

Comfrey (Symphytum spp.) is native to both Europe and Asia and has traditionally been used as both a food and forage crop. Three plant species in the genus Symphytum are medicinally relevant and include wild or common comfrey (Symphytum officinale L.), prickly or rough comfrey [Symphytum asperum Lepechin (Symphytum asperrimum Donn)], and Caucasian, Quaker, Russian, or blue comfrey [Symphytum × uplandicum Nyman (Symphytum peregrinum Lebed.)], which originated as a natural hybrid of Symphytum officinale L. and Symphytum asperum Lepechin.

Comfrey has traditionally been both applied to the skin (topically) for inflammation, pain and wound healing, and taken by mouth (orally) for gastrointestinal, respiratory and gynecological concerns.

Although evidence supporting oral use of comfrey is lacking, clinical trials suggest topical comfrey may be advantageous for pain and inflammation associated with injuries.

Although comfrey has been traditionally used both orally and topically, recent evidence suggesting carcinogenic and hepatotoxic effects has led to withdrawal of oral products from the market in many countries and warnings to avoid use on open wounds.

Evidence

DISCLAIMER:
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Inflammation:
Comfrey may have anti-inflammatory effects. Clinical trials investigating topical application of comfrey-containing creams have found significant reductions in inflammation and pain associated with sprains and muscle injuries. Additional study is needed to confirm these results.
Grade: B

Pain:
Comfrey may have anti-inflammatory effects. Clinical trials investigating topical application of comfrey-containing creams have found significant reductions in inflammation and pain associated with sprains and muscle injuries. Additional study is needed to confirm these results.
Grade: B

Myalgia:
A comfrey-containing cream has been applied on the skin to reduce pain associated with myalgia. Improvements in pain at rest and in motion were noted. Further studies are required before a firm recommendation can be made.
Grade: C